A payment is the transfer of an item of value from one party (such as a person or company) to another in exchange for the provision of goods, services or both, or to fulfill a legal obligation. In law, the payer is the party making a payment while the payee is the party receiving the payment. In trade, payments are frequently preceded by an invoice or bill.

Payment can take a variety of forms. Barter, the exchange of one good or service for another, is a form of payment. The most common means of payment involve use of money, check, or debit, credit or bank transfers. Payments may also take complicated forms, such as stock issues or the transfer of anything of value or benefit to the parties.

In general, the payee is at liberty to determine what method of payment he or she will accept; though normally laws require the payer to accept the country's legal tender up to a prescribed limit. Payment is most commonly effected in the local currency of the payee, unless if the parties agree otherwise. Payment in another currency involves an additional foreign exchange transaction. The payee may compromise on a debt, ie., accept a part payment in full settlement of a debtor's obligation, or may offer a discount, for example, for payment in cash, or for prompt payment, etc. On the other hand, the payee may impose a surcharge, for example, as a late payment fee, or for use of a certain credit card, etc.

The acceptance of a payment by the payee extinguishes a debt or other obligation. A creditor cannot unreasonably refuse to accept a payment, but payment can be refused in some circumstances, for example, on a Sunday or outside banking hours. A payee is usually obligated to acknowledge payment by producing a receipt to the payer. A receipt may be an endorsement on an account as "paid in full". The giving of a guarantee or other security for a debt does not constitute a payment.

Payments may be classified by the number of parties involved in a transaction. For example, a credit card transaction usually involves four parties (the purchaser, the seller, the issuing bank, and the acquiring bank). A cash payment requires a minimum of three parties (the seller, the purchaser, and the issuer of the currency). A barter payment requires a minimum of two parties (the purchaser and the seller).

A bank P (the payer) with a central bank nostro can pay directly to another bank R (the receiver) which has also a nostro with CB(Ccy) by instructing the central bank to make a payment of N[Ccy] (or an amount N in Ccy). The central bank however will only accept Ps payment instruction if the balance B on P's loro before the payment is B≥P. The payment itself is a booking in the accounts of the central bank where P's loro is debited with P (it will be B-P≥0 thereafter) and simultaneously Rs nostro is credit with P (its balance C will be C+P≥0 thereafter).

If the payer P maintains a loro account for another bank X, P can act as a payment agent for X: X instructs P to pay to R; then P instructs CB(Ccy) to pay on behalf of X: [X→P→CB→R].

In this example the first half of the payment is indirect and the second one (from CB(Ccy) to R) is still direct. If X would pay via P to R and finally to another party Y, the payment would be 'fully indirect': [X→P→CB→R→Y]. In practice, not every payment agent might have a direct nostro with the central bank, thus rather weird payment constellations can exist, which are hard to describe.

In 2005, an estimated $40 trillion globally passed through some type of payment system. Roughly $12 trillion of that was transacted through various credit cards, mostly the 21,000 member banks of Visa and MasterCard. Processing payments, including the extending of credit, produced close to $500 billion in revenue.[1] In 2012, roughly $377 trillion passed through noncash payment systems. This led to total account and transaction revenues close to $524 billion.[2]

In the U.S., debit cards are the fastest growing payment technology. In 2001, debit cards accounted for 9 percent of all purchase transactions, and this is expected to double to 18.82 percent in 2011.[3]

Historically, checks have been one of the primary means of payment for purchasing goods and services in the U.S. In 2001, cheques accounted for 25 percent of the U.S.-based payment mix; in 2006, this is projected at 17 percent.[4]

In the USA, a cheque as a form of payment can legally be refused for any reason (or no reason).[citation needed] Simply put: A payment via cheque is not a "payment" until the cheque was cashed and clears the banks. Example: You cannot order a fast food meal, throw a cheque on the counter and just leave with the meal, if they do not accept your payment via cheque, you would be committing larceny by taking the meal.

The timing of a payment has legal implication in some situations. For tax purposes, for example, the timing of a payment may determine whether it qualifies as a deduction in a taxpayer's calculation of taxable income in one year or the next.

For U.S. tax purposes, cash payments generally are taken to occur at the time of payment. Payment may also occur when a person transfers property or performs a service to the payee in satisfaction of an obligation.[5] A payment by check is normally deemed to occur when the check is delivered, as long as the check is honored on presentation by the payee. This rule also generally applies where the check is not presented to the bank until the next taxable year, and even though the payer could stop payment on the check in the meantime.[6]Postdated checks, however, are not considered payment when delivered.[7] Generally, payments by credit card take effect at the point of the sale and not when a payer is billed by the credit card company or when the payer pays the credit card company's bill.[8] A business that reports on an accrual basis, would report income in the year of sale though payment may be received in a subsequent year.

Payment of most fees to government agencies by cheque, if permitted, usually takes effect after a set number of days for clearance or until the cheque is actually cleared. Payments by credit card, if permitted, and cash payments take immediate effect. Normally, no other forms of payment are permitted or accepted.